A musical instrument that produces sound as a result of one object striking another is known as a “percussion” instrument. The striking object can be a person's hands/fingers, such as when one plays bongos or a piano. Or the striking object can be something held by a musician, such as a drum stick, mallet, or beater, for striking a drum or triangle, for example.
A percussion “controller” is an electronic device that senses impacts and pressures associated with performing musical rhythms using virtual music software and sound synthesis in conjunction with either computers or electronic musical instruments, such as synthesizers. The performer typically uses the controller to accompany other performers who are using other instruments, for example, trumpets, pianos, guitars, etc. In other words, an electronic drum set has both a percussion controller and a drum synthesizer. Triggered by the performer, the percussion controller sends messages, which contain information about pitch, intensity, volume level, tempo, etc., to devices that actually create the percussive sounds. Percussion controllers are available in a variety of different forms and vary widely in capabilities.
Basic percussion controllers typically include a set of resilient (e.g., rubber or rubber-like, etc.) pads that can be played with either drum sticks or the musician's hands and fingers. In some cases, these controllers are integrated with a synthesizer. In such cases, the synthesizer generates rhythm “signals,” which produce rhythm sounds after transmission to and playback over an audio system. The percussion controllers and synthesizer are sometimes federated (i.e., separate devices), which enables buyers to select a best controller and a best synthesizer from different manufacturers.
Percussion controllers may also be capable of receiving the triggering rhythm patterns on conventional percussion instruments, such as acoustic drum sets, cymbals, and hand drums. To do so, the acoustic instrument is typically equipped with electronic triggers.
Drummers can also choose to retrofit a traditional acoustic drum kit with a controller and drum/cymbal triggers. This enables the drummer to add his own acoustic accompaniment to the sounds generated by the controller, thereby creating rhythmic effects that would otherwise be impossible using traditional percussion instruments alone. Many drummers today are combining their acoustic drums with additional percussion controllers. This enables them to achieve the dynamics and responsive feeling attainable only from actual drums and cymbals, while also realizing the benefits of compactness and electronic convenience of triggered percussion sounds, like cow bells and ago-go bells, wood blocks, conga drums, gongs, tympani, and the like.
Although quite useful for expanding the sound-generating capabilities of a musician, currently-available percussion controllers are not without their limitations and drawbacks.
First, conventional percussion controllers sense the dynamics of impacts in a predefined physical impact zone that is instrumented with pressure- or force-detecting sensors. The controllers then process the sensor signals. This technique of electronic sensing captures only a limited part of the dynamic range of the percussions.
Also, to the extent that the percussion requires more sensors, such additional sensors can interfere with one another. Increased processing is required to remove this “cross-talk,” which further reduces the dynamic range available. In fact, the signal processing exhibits combinatorial growth for each additional sensor. This approach to sensing thus limits the ability of the controller to accurately capture a percussionist's performance, limits the number of impact zones available to the percussionist, and drives up the cost of the percussion controller itself.
The performer notices these limitations as occasional false notes and a general lack of realism responding to the thrown forces. A design that reduces the occurrence of false notes results in a reduction in dynamic responsiveness. Furthermore, the performer also notices a lack of tonal dynamic response to strike placement as compared with the way that acoustic percussion instruments naturally respond. Consider that a snare drum exhibits a continuum of tones depending on where the strike is placed. Typical percussion controllers offer one or two positional sound variations. Although rather impractical, it would take hundreds of sensors across a fourteen-inch-diameter surface to recreate the tonal location sensitivity of a single snare drum batter. The same locational sensitivity occurs for a ride cymbal (about 20 inches in diameter), for a hi-hat (about 14 inches in diameter), and perhaps to a lesser extent for crash cymbals and tom-toms. As a consequence, a trap-set percussion controller with realistic locational sensitivity would require many thousands of sensors.
Second, percussionists use many different techniques; for example finger throwing, finger muting, stick throwing, mallet throwing, etc. Conventional percussion controllers are custom designed for one or another of these techniques.
Further consideration of stick throwing reveals different striking techniques, such as by using the stick's tip, shank, or butt. Striking an acoustic percussion instrument using these different techniques results in different sounds. Conventional percussion controllers are unable to detect and respond differently to for these different percussive techniques.
Also, percussion instruments exhibit a wide variation of physical arrangements (e.g., a trap set, a snare drum, a triangle, maracas, a tympani, a xylophone, a piano, etc.). So, notwithstanding the flexibility potentially provided by an electronic implementation of an instrument, an electronic multi-percussionist will nevertheless be forced to purchase many different custom-designed percussion controllers (e.g., an electronic xylophone, an electronic trap-set, and an electronic hand-drum, etc.).
Third, a percussionist' ability to place a strike improves with training and practice. This improved ability enables a percussionist to direct a strike to increasingly specific (i.e., smaller) regions of an instrument with increasing accuracy. Unfortunately, existing custom-designed percussion controllers do not possess an ability to decrease the spacing between striking zones, which would enable the creation of additional striking zones. As a consequence, with improvement, the percussionist either compromises their abilities with the more basic controller or buys, at significant expense, a new controller more suitable to their improved abilities. A far more desirable alternative would be for the percussion controller to have the ability to adapt to the improving percussionist.
Discussion of Conventional Percussion Controllers
Roland Corporation HandSonic 15. This device is an electronic hand percussion multi-pad that, according to the manufacturer, permits a hand percussionist to play up to 600 acoustic and electronic percussion sounds, and up to 15 such sounds simultaneously. FIG. 1 depicts the pad of the HandSonic 15. As depicted, the pad, which is 10 inches in diameter, includes fifteen discrete regions or physical-impact zones, separated by indentations. The impact zones are arranged in a fixed configuration suited for hand percussion and finger percussion techniques, such as for Tabla or Conga. A pressure sensor, not depicted, is disposed under each physical-impact zone.
The mat absorbs some of the impact from the hand/fingers and creates a rebound or bounce to provide a more natural feel to the performer. Below the mat, and under each physical-impact zone, is an individual pressure sensor. A structural base is disposed beneath the sensors. There may be stiff shock-isolating devices integrated between the base and the sensor. A small processor samples all the sensors, and processes each sensor signal to adjust the sensor's sensitivity, remove noise, and most significantly remove the structure-borne cross-talk that occurs when the physical impact on one sensor is acoustically transferred through the sensor to the base and subsequently into adjacent sensors.
Alternate Mode Inc. trapKat. The HandSonic 15 includes a sound synthesizer, which is integrated with the sensor-signal processor. Some controllers, such as the trapKat electronic percussion system, do not integrate the synthesizer or provide the synthesizer as an option. In such products, the processor must send control signals to the synthesizer. In either case, when either an impact or a pressure is detected in a zone, the measured strength of the impact/pressure is mapped to a musical event message (typically in accordance with the MIDI protocol) that is sent to the synthesizer.
The trapKat, which is depicted in FIG. 2, is customized by the manufacturer to facilitate the “trap-set” style of percussion. The trapKat includes 24 physical-impact zones including zones that the percussionist can program for playing cymbals, tom-toms, snares, hi-hat, and ride cymbal, special tones (e.g., cow bell, wood bloc, rim click, etc.)
The HandSonic 15 by Roland Corporation and the trapKat by Alternate Mode Inc. are similar in the sense that they both: (1) have a single structural base, (2) have sensors beneath an impact surface that is arranged into predefined zones, (3) process the array of sensor signals to remove noise and crosstalk, (4) detect zone impacts or pressures, and (5) map the zone impacts/pressures into events for synthesis.
The trapKat is designed to accommodate thrown (drum) sticks, which changes the arrangement and dimensions of the physical-impact zones. Although the trapKat can be configured to be played using hand or finger-throwing techniques, and it can map its zones to hand-percussion sounds, it is not as well suited to hand percussion as the HandSonic 15. Since neither the trapKat nor the HandSonic 15 is well suited to accommodate both stick and hand techniques, a multi-percussionist using these techniques would require both of these percussion controllers.
Roland Corporation's TD-9KX2-S V-Tour Series Drum Set. A different approach to the trap-set percussion controller is illustrated by the TD-9KX2-S V-Tour Series drum set, depicted in FIG. 3. In this controller, the impact zones are federated and take the shape of real drum heads, rims and cymbals. The Ride cymbal and snare drum have two impact zones; the bell and mid-cymbal or the drum head and the rim. This collection of federated sensors and the sensor processor is the percussion controller. Often in this type of arrangement (as is the case for the TD-9KX2-S), the down-stream drum synthesizer is integrated with the sensor processor as a single device.
This federated sensor device approach features the ability for the percussionist to physically arrange and customize the layout of the physical-impact zones along structural rails. But the railing still couples structure-borne cross-talk from one impacted sensor to other sensors.
All the prior-art approaches to percussion controllers suffer certain common problems. In particular, a percussionist playing an acoustic percussion instrument performs with a very wide dynamic range, sometimes exceeding 120 dB, ranging from the barely audible “triple pianissimo” to the explosively loud “triple forte.” Sensors with such extreme dynamic range are very expensive. As a consequence, most percussion controllers use relatively less expensive sensors that disadvantageously cannot recreate such a broad dynamic range.
In summary, the drawbacks of existing percussion controllers include:                Limited dynamics. This is a consequence of the limited range of sensor dynamics. In addition, induced electromagnetic noise also limits the lowest end of the dynamic range for detecting the lightest impacts.        Crosstalk. Physical vibrational couplings exist between impact zones results in crosstalk between sensors. As a consequence, false notes get triggered. Crosstalk limits the ability to scale up the number of zones and limits the arrangement of the zones.        Time lag. A processor must process the sensor signals and remove cross-talk, map the threshold crossing signal to an event, then format an event message for transmission to a synthesizer. Consequently, in response to an impact, an inevitable artificial time lag is incurred before actually generating a sound.        Not reconfigurable. The size and number of impact zones is not reconfigurable. A professional percussionist can accurately place a strike inside a square 1¾% inches on each side while an amateur requires a much larger impact area. Fixed sensor-zone-dependent instrumented surfaces do not accommodate professional accuracy levels, do not accommodate the need for larger zones for novices, and do not adapt to the improving skill levels.        Multiple custom surfaces required. A trap-set layout is fundamentally different from vibraphone layout. A percussive fret-board (mallet percussion arranged like a guitar neck with ranks of frets) is fundamentally different from a xylophone/piano layout. This requires that electronic multi-percussionists purchase and haul multiple percussion controllers for a performance.        Instrumented surfaces cannot adequately sense a variety of different throwing techniques.        Instrumented surfaces with large numbers of physical-impact zones (>30) are very expensive.        Educational devices used for training percussion can only measure the timing of impacts; they do not provide training for the throwing techniques that percussionists need to master. Currently, a percussionist's throwing techniques can only be assessed in the presence of an instructor or expert.A need remains for a percussion controller that addresses at least some of the aforementioned drawbacks of existing percussion controllers.        